Could Earth Possibly Have More than One Moon?

May 08, 2009 18:38

The history of planet Earth is a fascinating story, involving catastrophic collisions with other small planets and a veritable plethora of asteroid impacts. The prevailing theory about the formation of the moon is called the giant impact hypothesis: the theory goes that a Mars-sized object, known as Theia, crashed in to the young Earth. What was left was Earth, and its moon.

A new computer model suggests, however, that the Moon may not have been the only reminder of that big collision. Jack J. Lissauera of the Space Science and Astrobiology Division, NASA Ames Research Center, and John E. Chambers of the Department of Terrestrial Magnetism, Carnegie Institution of Washington, have suggested that moonlets called Trojans may have been left behind in the collision.

"The giant impact that likely led to the formation of the Moon launched a lot of material into Earth orbit, and some could well have been caught in the Langrangian points," -points in space where the gravity between two objects cancels the other out, said says study team member Lissauer. Their theory places small moonlets, or Trojans, in Earth’s orbit, for up to 100 million years.

Over time, gravitational tugs from other planets would have eventually altered Earth’s orbit, even if it was only slightly. Thus, the Langrangian points would have altered, leaving the Trojans once again susceptible to gravity. From there, they could be anywhere by now, or destroyed entirely.

"The perturbations from the other planets are very, very tiny," said Lissauer. But they change the shape of Earth's orbit, which subsequently changes the effect that the Sun's gravity has on the moons, that "...is what ultimately destabilizes the Trojans."

A separate yet similar model created by Matija Cuk, an astrophysicist at the University of British Columbia in Canada has suggested that smaller, asteroid sized objects, only a few tens of kilometers in width, could have lasted longest in those stationary positions. She believes that they could have lasted a lot longer too, up to a billion years or more.

However she noted that “they would have looked more like Jupiter or Venus in the sky than a satellite. They would have resembled very bright stars.”

Introduction and Conclusion can cause the biggest problems for your research paper at college or university. You will be surprised, but the research part is not the most difficult one for a lot of students. The biggest problems they face when writing an Introduction and Conclusion. They don't know what can be included and what can't be included in these parts, while keeping a healthy balance between an introduction, body, and conclusion in terms of word count. Read more

Given the individuality and uniqueness of every person, some things in life have to be unified. White collars are to dress in the classic style to work, while pupils wear school uniform on a daily basis. This allows for consistency and accuracy in their respective institutions just like the formatting does in writing. For clear and digestible expression of ideas, essays follow a certain structure, consist of particular elements, and have a special layout. Read more

Bike ride is the most elementary form of transport. In earlier days, it was the first human powered vehicle that later transformed the face of automation. The first bicycle appeared around 400 years ago. Slowly innovation and technology shaped the rudimentary bicycle into the modern day road bike that we are so accustomed to see. Read more